Custom megaprosthetic replacement for proximal tibial tumours

Controversies and Challenges in the Management of Osteosarcoma-an Indian Perspective

Osteosarcoma (OGS) is the most common primary bone tumor in children and adolescents which requires a multidisciplinary approach to management. Although chemotherapy and surgery can cure more than half of localized OGS cases, the unique challenges faced by resource-limited countries like India make this outcome difficult to achieve. Various questions in the management of OGS including role of high-dose methotrexate (HDMTX) in neoadjuvant setting, triplet vs doublet chemotherapy, intensification of chemotherapy based on response in setting of doublet, and indigenous prosthesis in setting of limb salvage need to be defined. Similarly, in the metastatic and recurrent setting, questions regarding intent of treatment, indications of chemotherapy, timing of surgery, and role of targeted therapies need clarification. Lack of randomized trials from India makes definite conclusions difficult, but an attempt can be made to define the best approach in the Indian scenario from available evidence. Hence, a critical review of literature from India and the West was done to define possible management approaches and highlight the lacuna for future research.

Endoprosthetic replacement of the proximal tibia for oncological conditions

Aims

The proximal tibia (PT) is the anatomical site most frequently affected by primary bone tumours after the distal femur. Reconstruction of the PT remains challenging because of the poor soft-tissue cover and the need to reconstruct the extensor mechanism. Reconstructive techniques include implantation of massive endoprosthesis (megaprosthesis), osteoarticular allografts (OAs), or allograft-prosthesis composites (APCs).

Methods

This was a retrospective analysis of clinical data relating to patients who underwent proximal tibial arthroplasty in our regional bone tumour centre from 2010 to 2018.

Results

A total of 76 patients fulfilled the inclusion criteria and were included in the study. Mean age at surgery was 43.2 years (12 to 86 (SD 21)). The mean follow-up period was 60.1 months (5.4 to 353). In total 21 failures were identified, giving an overall failure rate of 27.6%. Prosthesis survival at five years was 75.5%, and at ten years was 59%. At last follow-up, mean knee flexion was 89.8° (SD 36°) with a mean extensor lag of 18.1° (SD 24°). In univariate analysis, factors associated with better survival of the prosthesis were a malignant or metastatic cancer diagnosis (versus benign), with a five- and ten-year survival of 78.9% and 65.7% versus 37.5% (p = 0.045), while in-hospital length of stay longer than nine days was also associated with better prognosis with five- and ten-year survival rates at 84% and 84% versus 60% and 16% (p < 0.001). In multivariate analysis, only in-hospital length of stay was associated with longer survival (hazard ratio (HR) 0.23, 95% confidence interval (CI) 0.08 to 0.66).

Conclusion

We have shown that proximal tibial arthroplasty with endoprosthesis is a safe and reliable method for reconstruction in patients treated for orthopaedic oncological conditions. Either modular or custom implants in this series performed well.

Cite this article: Bone Jt Open 2022;3(9):733–740.

Joint preservation surgery in grade 2 and 3 giant cell tumors of bone around the knee

Objective: To evaluate the clinical and functional outcomes of joint preservation surgery in high-grade giant cell tumors (GCT) around the knee joint. Methods: A retrospective review of 25 patients of high-grade GCT (Campanacci grade 2 and 3) involving proximal tibia or distal femur managed by extended curettage, bone grafting, and stabilization with knee spanning external fixator between 2016 and 2018 was done. The radiographic outcomes, functional outcomes (Musculoskeletal Tumor Society [MSTS] score for lower limb), and complications including donor site morbidity were evaluated. Results: The mean age of the patient population was 24.04 years with an average follow-up period of 30.24 months. Fourteen patients had involvement of distal femur, and 11 involved proximal tibia. There were 16 cases of grade 2 lesions and 9 cases of grade 3 lesions. Twenty-four out of the 25 patients had radiological consolidation of graft, while one patient had graft subsidence. Twenty-two out of 25 patients had full extension and knee flexion more than 100 degrees. The mean MSTS score was 25.2. Three patients had an MSTS score under 20. All three patients had an extension lag with a restricted range of motion. Conclusion: Joint preservation surgery, when done in line with the basic principles of tumor surgery, gives good radiographic and functional outcomes even in grade 2 and 3 giant cell tumors of bone around the knee and should be attempted before replacement surgeries.

Osteofibrous dysplasia and adamantinoma: A summary of diagnostic challenges and surgical techniques

Osteofibrous dysplasia is an indolent benign fibro-osseous tumor, while adamantinoma is a locally aggressive biphasic malignancy with epithelial and fibro-osseous components. Predominantly arising in the tibial diaphysis of children and young adults, both tumors are resistant to chemotherapy and radiation. Wide surgical resection is regarded as the mainstay of therapy for adamantinoma, and limb-salvage reconstructive procedures can achieve good functional outcomes, albeit with non-negligible rates of complications. This review discusses emerging advances in the pathogenesis, histogenesis, and diagnosis of these entities and presents advantages and limitations of the most common surgical techniques used for their management.

Compressive osseointegration for endoprosthetic reconstruction

This review summarizes the biomechanical concepts, clinical outcomes and limitations of compressive osseointegration fixation for endoprosthetic reconstruction. Compressive osseointe - gration establishes stable fixation and integration through a novel mechanism; a Belleville washer system within the spindle applies 400-800 PSI force at the boneimplant interface. Compressive osseointegration can be used whenever standard endoprosthetic reconstruction is indicated. However, its mode of fixation allows for a shorter spindle that is less limited by the length of remaining cortical bone. Most often compressive osseointegration is used in the distal femur, proximal femur, proximal tibia, and humerus but these devices have been customized for use in less traditional locations. Aseptic mechanical failure occurs earlier than with standard endoprosthetic reconstruction, most often within the first two years. Compressive osseointegration has repeatedly been proven to be non-inferior to standard endoprosthetic reconstruction in terms of aseptic mechanical failure. No demographic, device specific, oncologic variables have been found to be associated with increased risk of aseptic mechanical failure. While multiple radiographic parameters are used to assess for aseptic mechanical failure, no suitable method of evaluation exists. The underlying pathology associated with aseptic mechanical failure demonstrates avascular bone necrosis. This is in comparison to the bone hypertrophy and ingrowth at the boneprosthetic interface that seals the endosteal canal, preventing aseptic loosening.

Proximal tibial replacement in revision knee arthroplasty for non-oncologic indications

Proximal tibial metaphyseal bone loss compromises the alignment and fixation of components during revision total knee arthroplasty. In massive, segmental defects with loss of collateral ligamentous support and lack of bone to support the use of prosthetic augments or metaphyseal cones or sleeves, a hinged proximal tibial replacement or a so-called “megaprosthesis” should be available. While proximal tibial replacement is the reconstructive method of choice in the setting of bone tumor resection, applications in non-oncologic joint arthroplasty are rare and may offer an opportunity for limb salvage in dire clinical scenarios with massive proximal tibial bone loss. This report reviews 6 cases of proximal tibial replacement.

Mid- to long-term results of allograft-prosthesis composite reconstruction after removal of a distal femoral malignant tumor are comparable to those of the proximal tibia

PURPOSE

To compare the outcomes of allograft-prosthesis composite for reconstruction after malignant tumors at the distal femur and proximal tibia.

METHODS

Case-control study of 24 patients with distal femur tumor and 21 with proximal tibia tumor. Union of the allograft-host interface was assessed by the International Society of Limb Salvage criteria, and complications according Henderson. Functional outcome was evaluated by the Musculoskeletal Tumor Society (MSTS) score, Western Ontario and McMaster Universities (WOMAC) score, and pain by a visual analog scale.

RESULTS

The median follow-up in the femoral group was 11.4 (range 2.3-25.0) years, and 10.1 (range 2.2-25.0) in tibial group. Incorporation of the allograft was successful in more than 90% in both groups. Tumor location was not significant predictor for allograft failure in multivariate analysis. Aseptic prosthesis loosening occurred in two patients in either group, and another patient in the tibial group had a breakage of the tibial insert. Excluding local recurrences and amputations, the prosthesis survival at 10 years was 94.1% in the femoral group, and 83.3% in the tibial group (n.s.). For the patients with preserved limb, the median MSTS score was 23.6 in the femoral group and 22.8 in tibial group (n.s.). Likewise, there were no significant differences in median WOMAC score (n.s.) or VAS pain (n.s.).

CONCLUSIONS

Allograft-prosthesis composite is an effective procedure for distal femur tumors related to the graft, prosthesis survival, and functional outcomes. The results are comparable to those for proximal tibial tumors.

LEVEL OF EVIDENCE

Therapeutic study, Level III.

Vascularized fibular medialization for reconstruction of the tibial defects following tumour excision

PURPOSE

The purpose of this study was to evaluate the functional and oncologic results of fibular medialization when used alone as a single-stage reconstructive technique after wide excision of malignant tumours of the proximal, middle, or distal tibia.

METHODS

Between December 2010 and May 2015, 14 patients (six males and eight females) with primary malignant tumours of the tibia (eight proximal, four diaphyseal, two distal) were treated by wide excision. The mean age of the patients at the time of surgery was 23.2 years (11-38). The fibula was mobilized medially with its vascular pedicle to fill the defect and was fixed by a long plate and screws bypassing the graft. The average size of the defects reconstructed was 19.5 cm (18-22). Patients were evaluated functionally using the Musculoskeletal Tumour Society (MSTS) scoring system.

RESULTS

The mean follow-up period was 31.3 months (range, 17-54). The average time for complete union was 7.6 months (range, 6-9). At final follow-up all patients had fully united grafts; 11 walked without aids. Chest metastases developed in one patient, superficial wound infection in two patients and leg length discrepancy in four patients; one case had LLD of more than 3 cm. The mean MSTS score was 23/30 points (76.5%). The minimum score was 40% (12/30) and the maximum was 90% (27/30).

CONCLUSIONS

Ipsilateral pedicled vascularized fibular centralisation or medialization is a durable reconstruction for tibial defects after wide excision of bone tumours with an acceptable functional outcome. Stable osteosynthesis is the key to union.

Poor prognosis and complications are common in limb salvage surgery for malignant tumors of the proximal tibia invading the fibula

BACKGROUND

Malignant tumors in proximal tibia invading fibula usually have a large tumor volume and are adjacent to the neurovascular bundles. The prognoses and functional outcomes of limb salvage for these patients are uncertain. We, therefore, asked whether patients with limb salvage surgery for malignant tumors in proximal tibia invading fibula had poorer oncological prognosis, higher complication rate, and lower postoperative functional score compared with patients without fibula invasion.

METHODS

We retrospectively reviewed 129 patients with primary malignant tumors in proximal tibia. The patients were divided into two groups, i.e., with and without proximal fibula invasion. A total of 35 and 94 patients were in the group with and without fibula invasion, respectively. Data on demography, operation time, blood loss volume, complications, survival time, and postoperative function were compared between two groups.

RESULTS

The patients with fibula invasion had a longer mean operative time (p = 0.011), less percentage of obtaining wide surgical margin (p = 0.027), lower estimated 5-year survival rate (p = 0.05), higher tumor local recurrence rate (p = 0.042), and earlier postoperative complications (p = 0.01) than the patients without fibula invasion. The difference in postoperative functions as evaluated by the Musculoskeletal Tumor Society functional scoring system was not significant (p = 0.233).

CONCLUSION

Patients with limb salvage surgery for malignant tumors in proximal tibia invading fibula had poorer oncological prognosis, higher complication rate, and acceptable postoperative functions compared with patients without fibula invasion.

Comparison between Constrained and Semiconstrained Knee Allograft-Prosthesis Composite Reconstructions

Allograft-prosthesis composite (APC) can restore capsular and ligamentous tissues of the knee sacrificed in a tumor extirpation. We asked if performing APC would restore knee stability and allow the use of nonconstrained arthroplasty while preventing aseptic loosening. We retrospectively compared 50 knee APCs performed with non-constrained revision knee prosthesis (Group 1) with 36 matched APCs performed with a constrained prosthesis (Group 2). In Group 1, the survival rate was 69% at five and 62% at ten years. Sixteen reconstructions were removed due to complications: eight deep infections, three fractures, two instabilities, one aseptic loosening, one local recurrence, and one nonunion. In Group 2, the survival rate was 80% at five and 53% at ten years. Nine reconstructions were removed: 3 due to deep infections, 3 to fractures, and 3 to aseptic loosening. In both groups, we observed more allograft fractures when the prosthetic stem does not bypass the host-donor osteotomy (P > 0.05). Both groups had mainly good or excellent MSTS functional results. Survival rate and functional scores and aseptic loosening were similar in both groups. A rotating-hinge APC is recommended when host-donor soft tissue reconstruction fails to restore knee instability. The use of a short prosthetic stem has a statistical relationship with APC fractures.

Functional outcome of limb salvage surgery with mega-endoprosthetic reconstruction for bone tumors

BACKGROUND

The use of a mega-endoprosthesis has become the method of choice for reconstruction after bone tumors. In this study, we sought to determine the functional outcome and complications associated with mega-endoprosthesis.

METHODS

A retrospective review of the charts of 16 patients who had undergone resection of bone tumors followed by reconstruction with mega-endoprosthesis between 2006 and 2011 was performed. Functional evaluation was based on the Musculoskeletal Tumor Society (MSTS) scoring system. Complications of the procedures were also analyzed.

RESULTS

Eight men and eight women at an average age of 36.7 years were included in the study. The tumor involved lower limb in 14 patients and upper limb in 2 patients. The average MSTS functional score was 72.3 ± 15. Excellent results were achieved in six patients, good in five, moderate and fair in two each and poor in one. Complications occurred in eight patients. Two patients had aseptic loosening of the femoral component of total knee replacement. Flap necrosis occurred in two patients, both of whom required latissimus dorsi free flap for coverage of total knee prosthesis. One patient underwent revision of femoral component subsequent to knee dissociation. Local recurrence of tumor, patellar tendon rupture and foot drop occurred in one patient each.

CONCLUSION

Mega-endoprosthetic reconstruction in limb salvage provides good functional outcome in patients with bone tumors.

Cause of infection in proximal tibial endoprosthetic reconstructions

INTRODUCTION

The underlying cause of proximal tibial prosthetic failure by infection is unclear. We asked: (1) Is resection amount related to prosthetic infection? (2) What other risk factors are related with infection? (3) What are the survivorship and functional outcomes of proximal tibial endoprosthetic reconstruction?

METHODS

Sixty-two patients who underwent modular proximal tibial megaprosthesis reconstruction were analyzed. Follow-up duration averaged 98 months (range 26-240 months). Associations between prognostic variables and prosthesis survival were assessed.

RESULTS

The 10-year prosthetic survival of the 62 implants was 73.9 ± 11.7%. Prostheses were removed in 16 (25.8%) patients for infection and 3 of the 16 underwent amputation. Resection of >37% (P = 0.016) of the tibia was found to be related to infection. Application of chemotherapy (P = 0.912) and use of synthetic material to fix the patella tendon (P = 0.2) were not found to influence prosthetic survival. Functional outcomes (determined by the MSTS system) of the 52 patients that maintained a mobile joint averaged 24.2 (81%) (range 18-28).

CONCLUSIONS

Our study suggests that the amount of bone resection is related with prosthetic failure by infection, however, the contribution of other risk factors should not be underestimated.

Soft-tissue management with immediate free flap transfer in segmental prosthetic replacement of proximal tibia sarcomas

Knee reconstruction with endoprosthesis after tumor resection is accepted as superior when compared with the other methods. But sometimes soft tissue reconstruction would be a challenging problem in this way of treatment. Five patients who were operated for tumor resection in this location, followed by reconstruction were presented with their one-year post operative results. Four latissimus dorsi and one rectus abdominis myocutaneous free flaps were used in these patients in order to manage soft tissue problems. All patients underwent chemotherapy in postoperative period. All flaps were successful in one year post operative examination. In this report we would like to stress the importance of surgical planning and soft tissue reconstruction of a specific patient population. We think that large musculocutaneous flaps such as latissimus dorsi and rectus abdominis musculocutaneous flaps should be preferred in soft tissue reconstruction of knee region after tumor resection followed by prosthetic replacement. Additionally, this way of treatment is superior when compared to the other methods in order to prevent complications such as prosthesis exposure or infection.

Failure mode classification for tumor endoprostheses: retrospective review of five institutions and a literature review

BACKGROUND

Massive endoprostheses provide orthopaedic oncologists with many reconstructive options after tumor resection, although failure rates are high. Because the number of these procedures is limited, failure of these devices has not been studied or classified adequately. This investigation is a multicenter review of the use of segmental endoprostheses with a focus on the modes, frequency, and timing of failure.

METHODS

Retrospective reviews of the operative databases of five institutions identified 2174 skeletally mature patients who received a large endoprosthesis for tumor resection. Patients who had failure of the endoprosthesis were identified, and the etiology and timing of failure were noted. Similar failures were tabulated and classified on the basis of the risk of amputation and urgency of treatment. Statistical analysis was performed to identify dependent relationships among mode of failure, anatomic location, and failure timing. A literature review was performed, and similar analyses were done for these data.

RESULTS

Five hundred and thirty-four failures were identified. Five modes of failure were identified and classified: soft-tissue failures (Type 1), aseptic loosening (Type 2), structural failures (Type 3), infection (Type 4), and tumor progression (Type 5). The most common mode of failure in this series was infection; in the literature, it was aseptic loosening. Statistical dependence was found between anatomic location and mode of failure and between mode of failure and time to failure. Significant differences were found in the incidence of failure mode Types 1, 2, 3, and 4 when polyaxial and uniaxial joints were compared. Significant dependence was also found between failure mode and anatomic location in the literature data.

CONCLUSIONS

There are five primary modes of endoprosthetic failure, and their relative incidences are significantly different and dependent on anatomic location. Mode of failure and time to failure also show a significant dependence. Because of these relationships, cumulative reporting of segmental failures should be avoided because anatomy-specific trends will be missed. Endoprosthetic design improvements should address failure modes specific to the anatomic location.

Cemented endoprosthetic reconstruction of the proximal tibia: how long do they last?

BACKGROUND

The few available studies documenting the long-term survival of cemented proximal tibial endoprostheses for musculoskeletal tumors do not differentiate between stem designs or patient diagnosis. There is wide variation in survival rates reported, possibly a result of this heterogeneity in patient population and implant design.

QUESTIONS/PURPOSES

We therefore asked: (1) How long do proximal tibial endoprostheses last? (2) What is the typical long-term functional result after proximal tibial replacement? And (3) what are the short- and long-term complications associated with endoprosthetic reconstruction of the proximal tibia, particularly with respect to the soft tissue reconstruction?

PATIENTS AND METHODS

We retrospectively reviewed 52 patients with 52 proximal tibial endoprosthetic reconstructions for a tumor-related diagnosis. Kaplan-Meier survivorship analysis was performed using revision of the stemmed components for any reason as an endpoint for implants, and death due to disease progression for patients. Function was assessed using the MSTS scoring system. The minimum followup was 1 month (mean, 96 months: range, 1-284 months; median, 69 months).

RESULTS

Using revision of the stemmed components for any reason as an end point, overall prosthesis survival at 5, 10, 15, and 20 years was 94%, 86%, 66%, and 37%, respectively. The 29 modular implants demonstrated a trend toward improved survival compared to the 23 custom-designed components, with a 15-year survivorship of 88% versus 63%. The mean postoperative Musculoskeletal Tumor Society score at most recent followup was 82% of normal function (mean raw score, 24.6; range, 4-29).

CONCLUSIONS

Cemented endoprosthetic reconstruction of the proximal tibia provides a reliable method of reconstruction following tumor resection.

Proximal tibia osteoarticular allografts in tumor limb salvage surgery

BACKGROUND

Resection of large tumors of the proximal tibia may be reconstructed with endoprostheses or allografts with fixation. Endoprosthetic replacement is associated with high failure rates and complications. Proximal tibia osteoarticular allografts after tumor resection allows restoration of bone stock and reconstruction of the extensor mechanism, but the long-term failure rates and complications are not known.

QUESTIONS/PURPOSES

We therefore determined (1) the middle- and long-term survival of proximal tibia osteoarticular allografts, (2) their complications, and (3) functional (Musculoskeletal Tumor Society score) and radiographic (International Society of Limb Salvage) outcomes in patients treated with this reconstruction.

PATIENTS AND METHODS

We retrospectively reviewed 52 patients (58 reconstructions including six repeat reconstructions) who underwent osteoarticular proximal tibia allograft reconstructions after resection of a bone tumor. The minimum followup of the 46 surviving patients was 72 months (mean, 123 months; range, 10-250 months). Survival of the allograft was estimated using the Kaplan-Meier method. We documented outcomes using the Musculoskeletal Tumor Society functional scoring system and the International Society of Limb Salvage radiographic scoring system.

RESULTS

Six patients died from tumor-related causes without allograft failure before the 5-year radiographic followup. At last followup, 32 of the 52 remaining allografts were still in place; 20 failed owing to infections, local recurrences, or fractures. Overall allograft survival was 65% at 5 and 10 years, with an average Musculoskeletal Tumor Society functional score of 26 points and an average radiographic result of 87%.

CONCLUSIONS

Based on these data we believe proximal tibia osteoarticular allograft is a valuable reconstructive procedure for large defects after resection of bone tumors.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Compressive osseointegration of tibial implants in primary cancer reconstruction

Compressive osseointegration technology, which provides immediate, mechanically compliant endoprosthetic fixation, has been adapted for massive proximal tibial reconstructions in an attempt to avoid aseptic failure encountered with conventional stems. A retrospective review of 16 patients with resected tumors was undertaken to determine whether compressive osseointegration can provide durable anchorage of tibial implants. Medical records, radiographs, and clinical examinations were reviewed to assess surgical, local disease control, and prosthetic outcomes. The average age was 18 years (range, 12-42 years). Diagnoses included osteosarcoma (12), Ewing sarcoma (two), chondrosarcoma (one), and undifferentiated sarcoma (one). Minimum followup was 2 years (mean, 4.5 years; range, 2-10.3 years); no patient was lost to followup. There were no local recurrences. Four patients developed metastatic disease; one patient died of his primary tumor, and another died from a chemotherapy-related malignancy. Complications included one early deep infection that ultimately resulted in prosthetic loosening and the need for an above-knee amputation. There were two late deep infections; prosthetic retention was achieved with débridement and antibiotics. One patient developed aseptic loosening and underwent revision; the other 15 implants provided stable osseointegration at last followup. Compressive osseointegration technology can thus achieve acceptable short-term endoprosthetic fixation results and may reduce the risk of aseptic loosening reported with conventional tibial stems.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Endoprosthetic reconstruction using total femoral custom mega prosthesis in malignant bone tumours

We analysed 17 patients with primary malignant bone tumour of the femur who underwent limb salvage surgery with the total femoral custom mega prosthesis during the period 1994-2008. The patients were in the age group of 12-73 years, with a mean age of 30.94 years. There were 14 males. The most common diagnosis was osteosarcoma. The average follow-up period was 54.05 months with the longest being 168 months. The average Musculoskeletal Tumour Society (MSTS) functional score was 66.6%. The two- to 14-year overall survival was 82.4%. Three patients died of disease and one patient required amputation. Complications encountered were deep infection and dislocation of the prosthesis.

Implant design and resection length affect cemented endoprosthesis survival in proximal tibial reconstruction

Endoprosthetic reconstruction of the proximal tibia continues to pose many challenges. A retrospective analysis of 44 consecutive patients who underwent cemented proximal tibial replacement were included to investigate if patient age, surgical stage, type of implant, stem diameter, or resection length could be associated with implant failure. Fifteen patients (34%) suffered prosthetic failure, 7 due to infection. Prosthetic-related complications occurred in 13 patients (30%). Custom design prosthesis and longer length of resection were significantly associated with prosthesis survival in a Cox regression analysis (P = .001, hazard ratio = 8.747 and P = .044, hazard ratio = 1.217, respectively). Cemented proximal tibial replacement offers a functional knee, but reducing risk of complications still remains challenging. Prosthetic design and length of resection affect overall cemented endoprosthesis survival.

The long-term results of endoprosthetic replacement of the proximal tibia for bone tumours

We have investigated whether improvements in design have altered the outcome for patients undergoing endoprosthetic replacement of the proximal tibia following resection of a tumour. Survival of the implant and 'servicing' procedures have been documented using a prospective database. A total of 194 patients underwent a proximal tibial replacement, with 95 having a fixed-hinge design and 99 a rotating-hinge with a hydroxyapatite collar; their median age was 21.5 years (10 to 74). At a mean follow-up of 14.7 years (5 to 29), 115 patients remain alive. The risk of revision for any reason in the fixed-hinge group was 32% at five years, 61% at ten years and 75% at 15 and 20 years, and in the rotating-hinge group 12% at five years, 25% at ten years and 30% at 15 years. Aseptic loosening was the most common reason for revision in the fixed-hinge knees, fracture of the implant in the early design of rotating hinges and infection in the current version. The risk of revision for aseptic loosening in the fixed-hinge knees was 46% at ten years. This was reduced to 3% in the rotating-hinge knee with a hydroxyapatite collar. The cemented, rotating hinge design currently offers the best chance of long-term survival of the prosthesis.

Allograft-prosthetic composite in the proximal tibia after bone tumor resection

We consider an allograft-prosthesis composite in the proximal tibia one of the better reconstructive options in this site because it combines the mechanical stability of a prosthesis with the biologic reconstruction of the extensor mechanism. We retrospectively reviewed 62 patients who had proximal tibia reconstructions with allograft-prosthesis composites to ascertain the complications and functional outcomes. By combining an allograft with a prosthesis, placing cement in the graft, and press-fitting the prosthesis in the tibial diaphysis, we obtained satisfactory Musculoskeletal Tumor Society scores in 90.4% of patients, with a 5-year survival rate (73.4%) comparable to that of reconstruction with a modular prosthesis. However, we observed high infection rates (24.2%) and rotation of the medial gastrocnemius seemed not to reduce this complication. For this reason, we do not recommend using this reconstructive technique in patients who will receive postoperative chemotherapy or in patients in whom a previous reconstructive method failed. We believe the ideal candidate is the young patient with a benign aggressive or malignant low-grade tumor who has not undergone previous surgery.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Allograft-prosthesis composites after bone tumor resection at the proximal tibia

The survival of irradiated allograft-prosthesis composites at the proximal tibia is mostly unknown. However, allograft-prosthesis composites have proved beneficial at other reconstruction sites. We presumed allograft-prosthesis composites at the proximal tibia would improve survival and facilitate reattachment of the extensor mechanism compared with that of conventional (megaprostheses) reconstructions. We retrospectively reviewed 26 patients who underwent resection of proximal tibia tumors followed by reconstruction with allo-graft-prosthesis composites. Patients received Guepar massive custom-made fully constrained prostheses. Allografts were sterilized with gamma radiation, and the stems were cemented into the allograft and host bone. The minimum followup was 6 months (median, 128 months; range, 6-195 months). Fourteen patients had one or more components removed. The median allograft-prosthesis composite survival was 102 months (95% confidence interval, 64.2-infinity). Of the 26 allografts, seven fractured, six showed signs of partial resorption, and six had infections develop. Seven allografts showed signs of fusion with the host bone. Six extensor mechanism reconstructions failed. Allograft-prosthesis composites sterilized by gamma radiation yielded poor results for proximal tibial reconstruction as complications and failures were common. We do not recommend irradiated allograft-prosthesis composites for proximal tibia reconstruction.

Aseptic loosening is uncommon with uncemented proximal tibia tumor prostheses

Aseptic loosening is a frequent cause of failure of cemented proximal tibia tumor endoprostheses. Uncemented prostheses may lessen this risk. We identified complications including aseptic loosening that affected prosthetic survival, limb survival and functional outcome for 44 consecutive patients after sarcoma resection from the proximal tibia and uncemented endoprosthetic reconstruction. At a mean final followup of 60 months (range, 9-152 months), there were no cases of aseptic loosening. Twelve (27%) patients suffered 14 complications leading to prosthetic failure due to infection (n = 7), stem fracture (n = 2), rotational instability (n = 1), vascular compromise (n = 2) and local tumor relapse (n = 2). However, limb salvage was successful in 37 of 44 (84%) patients. Functional assessment for 35 patients revealed a mean Toronto Extremity Salvage Score of 77/100 (range, 33-98) and Musculoskeletal Tumor Society 1987 and 1993 scores of 25/35 (range, 13-31) and 75/100 (range, 33-97), respectively. Mean knee joint flexion was 91 degrees (range, 0-110 degrees ) and knee extension lag was 6 degrees (range, 0-30 degrees ). Three patients with knee extensor complications had inferior functional outcomes. Aseptic loosening is uncommon with uncemented proximal tibia reconstruction, but decreasing other complications at this location remains challenging.

LEVEL OF EVIDENCE

Therapeutic study, level IV-1 (case series).

Lower limb salvage surgery: modular endoprosthesis in bone tumour treatment

We retrospectively analysed 90 patients who underwent "en bloc" resection and modular endoprosthesis reconstruction in the lower limbs between 1987-2003. After proximal femur resection, reconstruction was performed with a modular endoprosthesis by Howmedica (KFTR, designed by Kotz) and modular revision endoprosthesis by W. Link or Lima-Lto (Revision system, designed by Wagner). The knee joint was reconstructed with a modular endoprosthesis (Howmedica, KFTR designed by Kotz) after distal femur or proximal tibia resection. Malignant bone tumours were present in 58 patients (64.5%), benign tumours in 16 (17.8%), metastases in 8 (8.9%), tumour-like lesions in 4 (4.4 %) and non-tumour-related destruction of the femur in 4 patients (4.4%). High-grade tumours were found in the majority of malignant bone tumours (70.7%). Treatment complications, which occurred in 26 patients, were: local recurrence of the tumour, deep infection, acetabular destruction following hemiarthroplasty, recurrent dislocations of endoprosthesis, periprosthetic fracture and hardware problems. In total, 23 patients (25.6%) died due to tumours. Endoprostheses should be considered as a treatment of choice for bone tumours in the hip and knee joint region. Advances in limb salvage surgery are, and will long continue to be, a great challenge for orthopaedic oncologists of the 21st century.

Survival of total knee replacement with a megaprosthesis after bone tumor resection

BACKGROUND

The use of a megaprosthesis has become the method of choice for reconstruction after bone tumor resection at the knee. However, the long-term survival of megaprostheses is poor. In this study, we sought to identify factors that were associated with implant failure and amenable to interventions designed to improve implant survival.

METHODS

A retrospective review of the charts of ninety-one patients who had undergone resection of a tumor of the knee followed by reconstruction with a custom-made megaprosthesis was performed. The distal part of the femur was resected in fifty-six patients and the proximal part of the tibia, in thirty-five patients. The reconstruction was performed with an allograft-prosthesis composite in thirty-three patients and with metal or plastic sleeves in fifty-eight patients. Reconstruction of the extensor mechanism was necessary in all thirty-five patients with a tibial tumor.

RESULTS

The median duration of follow-up was sixty-two months. The extensor mechanism was significantly less likely to rupture when partial continuity had been preserved at the time of the resection. Intra-axial laxity (an arc of motion of >5 degrees in the frontal plane) was significantly more common when the prosthesis had an antirotation pin than when it did not have an antirotation pin (p = 0.0023). There was mechanical failure of ten allograft-prosthesis composites and ten sleeve reconstructions. Thirty-six patients had removal of at least one component of the prosthesis. When revision due to local tumor recurrence was excluded, the median duration of prosthetic survival was 130 months following the distal femoral resections and 117 months following the proximal tibial resections. The median duration of survival was 117 months for the allograft-prosthesis composites and 138 months for the sleeve reconstructions. Body weight and activity level were independent predictors of early revision.

CONCLUSIONS

The long-term survival of the knee megaprostheses in this study was poor. Mechanical failure was multifactorial and the leading cause of revision. Use of allograft-prosthesis composites and use of bushings or an antirotation pin appeared to have no mechanical benefits. We recommend that weight control programs and advice about adapting their activity level be offered to patients preoperatively.

Surgical options and outcomes in bone sarcoma

Bone sarcomas are challenging to treat. The primary goal of treatment is local control of the disease while, if possible, achieving salvage of the limb and its function. There is no ideal method of reconstruction in limb-salvage surgery but the choice of the method of reconstruction should be individualized based upon many factors including the patient's age, the extent and location of the tumor, the wishes of the patient, and the availability of surgical facilities and expertise, as well as the cost of the procedure. In this review, the authors explore the advantages and disadvantages of the different methods of limb reconstruction. The surgical management of bone sarcomas is a real challenge to the orthopedic surgeon, owing to the diversity of sites in which tumors arise, combined with the extension of the tumor into adjacent soft tissues and their proximity, in many cases, to major neurovascular structures. There have been dramatic improvements in survival for patients with osteosarcoma and Ewing's sarcoma in the past 30 years owing to increasing effectiveness of chemotherapy. This, along with developments in imaging techniques (magnetic resonance imaging in particular) has led to earlier diagnosis and more accurate preoperative staging. Whilst traditional treatment for bone tumors used to be amputation, advances in surgical techniques have made limb-salvage procedures a valid alternative method of treatment to amputation in 80-85% of patients with primary bone sarcomas.

Distal femoral tumours treated by resection and custom mega-prosthetic replacement

We have analysed the results of 246 cases of distal femoral tumours treated by resection and prosthetic replacement between 1988 and 2002. Patient ages ranged from 6-67 years averaging 24 years; 133 were males. The most common tumour was osteosarcoma (67% of patients). The follow-up ranged from 2 to 14 years. Stage II tumours were seen in 72% of patients. The technique of sleeve resection of the quadriceps musculature was followed to achieve local clearance of the tumour. The prosthesis used was a rotating hinge custom mega-prosthesis manufactured locally. The functional result achieved was excellent or good in 87%; 86% of the patients had no evidence of disease, and 13% had died. The 10-year patient survival was 76.9%. Periprosthetic fracture and infection were the most common complications.